Radiation-balanced lasing in Yb:YAG and Yb:KYW.

Radiation-balanced lasing and thermal profiling is reported in two Yb-doped laser crystals at room temperature. In 3% Yb:YAG a record efficiency of 30.5% was achieved by frequency-locking the laser cavity to the input light.

Laser cooling of Yb:KYW.

We report the first observation of laser cooling in Yb:KYW and validate the results by comparison with experiments in the well-studied material Yb:YAG. Radiation from a single-mode Ti:AlO laser was used to achieve cooling of 1.5 K/W in 1% Yb:KYW at 1025 nm, comparing well with the reference material 3% Yb:YAG which cooled by 3.